This invention relates to pulse code modulation (PCM) systems of communication.
With the advent of integrated circuit techniques it is now possible to make extremely compact PCM codecs (coder/decoders). Indeed a single channel codec can be incorporated in a conventional telephone instrument if desired, thus enabling the construction of an all-digital telephone system. Such a system may be used as a normal voice communication system or, with suitable adaptors, the telephone instruments may be used as data terminal devices.